Map lichen

Map lichen ( Rhizocarpon geographicum )

The map lichen ( Rhizocarpon geographicum ) is a lichen that grows directly on bare rock.

Description

The map lichen is a Krustenflechte, the thallus is close to the substrate or by growing them. The species is bright yellow to olive green. You can cover large areas on stones. The lichen is divided into small angular fields that are separated by a black border and pull through the lichen body. At the edge of the fields edged black fruiting bodies are sunk.

How many lichens it has an extremely slow growth. It grows depending on location per year only 0.25-0.6 mm radially outward. You can reach an age to over 1,000 years and will therefore be used for dating the decline of glaciers. The growth rate of a single location is known, the last ice cover can be calculated on the basis of the largest pieces.

Location

As location acidic silicate rock is preferred. In lower altitudes and in limestone areas this lichen occurs very rarely, and then only in low coverage. She comes from the coast before the world to the high mountains.

Botany

There are several subspecies

• R. geographicum (L. ) DC. ssp. arcticum ( Runemark ) Hertel
• R. geographicum (L. ) DC. ssp. diabasicum ( Räsänen ) Poelt & Vězda
• R. geographicum (L. ) DC. ssp. frigidum ( Räsänen ) Hertel
• R. geographicum (L. ) DC. ssp. geographicum
• R. geographicum (L. ) DC. ssp. kittilense ( Räsänen ) R.Sant.
• R. geographicum (L. ) DC. ssp. lindsayanum ( Räsänen ) R.Sant.

Special

The map lichen was recently elected by the members of the Working Group on e Bryologisch - lichenologischen for Central Europe V. ( BLAM ) for lichen of the year 2014.